Valve stem for gas engines



June 8 ,1926. 1,587,991

R. L. SPITZLEY ET AL VALVE STEM FOR GAS ENGINES Filed Nov. 15, 1924 ATT RNEY.

Patented June 8, 19 26. 7

UNITED STATES PATENT, FFICE.

'RAY L. SPITZLEY AND'ALLEN M. THOMPSON, OF DETROIT, MICHIGAN, ASSIGNORS TO ALLOYSIOUNDRY'COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHI- VALVE STEM r03 eAs ENGINES.

Application filed November 15, 1.924. Serial No. 750,131.

The object of our invention is to produce a valve stem adapted for making cast-in valves, and which is provided with a special threaded section thereon to insure a perma nent and rigid connection with the valve disc cast thereon, and to prevent any turning of the valve stem therein in case fusion I between the parts should not be complete.

Another object is to produce a valve stein adapted for casting-the valve disc thereon, having a special threaded section to prevent any turning within the disc, and so designed as to easily fuse portions of the threads with the molten alloy when the valve disc is case thereon.

A further object is to produce a valvestem that is simple in construction, easily manufactured, efficient in its purpose and that can be manufactured at a low cost.

The several objects are attained in the preferred form by the construction as more fully hereinafter set forth. 7

Similar parts on all drawings aremarked by similar numerals.

Fig. 1, illustrates the type of valve to which our valve stem is specially adapted.

Fig. 2 is a top view of the valve disc 7 showing the relative position of the stem.

Fig. 3 is'a sectional view ,-AA of Fig;

2 showing the valve, stem is cast in the valve disc.

Fig. 4, is an enlarged detail of the threaded section of the valve stem, showingthe special construction and arrangement of the threads.

Fig. 5'is a top view ofthe valve stem in Fig.4. a

We will now describe more fully the detailed construction of the. valve stem, and its application to cast-in'valves, referring to the drawings and the marks thereon.

It is general practice in manufacturing of certain types of two pieced valves for gas engine use, to use a machined steel valve stem and mold or cast an alloy valve disc thereon. For this construction it requires a valve stem having some kind of projections thereon for making a permanent and rigid connection within the cast valve disc, and sodesigned that fusion betweenthe two metals will take place without destroying or disturbing the surface of the valve stem when the molten alloy disc is cast thereon. And further, some means to prevent the valve stem from turning'or loosening within the valve disc, should the. alloy disc to fuse to the valve stem when cast;

The general construction of our valve stem comprises a machined cylindrical steel stem, having a double semi-threaded section formed on one end thereof, so arranged that alternate thread sections are formed at'di-f- Y ferent angles with the axis of the valve'stem.

The ends of each thread section overlapping the ends of the alternate adjacent thread section.

The stem -1 is a machined cylindrical rod, made of steel" of a quality suitable for the purpose for whichit is used, turned to any desired dimensions, and having a double semi-threaded section formed on one end thereof. The'section comprising a series of right hand thread segments 2 cut on one half of the cylindrical rod, and a series of left hand thread segments 3'cut on the opposite side of the rod 1, the thread segments are so arranged as to allow both the right'and the left hand section to extend slightly more than half the circumference of the rod '1, causing an overlapping of the segment ends, and an interweaving of the alternate right and left hand segment threads','by having one'end of each of the right hand thread segments above the end of the adjacent left "hand thread segrnent I and the opposite end of the right hand thread segment below the corresponding end of the left hand thread segment, formingan alternate interlocking of the righthand and the left hand thread segments as, were formed on opposite sides of the valve stem rod. The threaded sections 2-'- and -3 are formed of the V-typed threads, 'cutto a sharp thin edge, which will instantly melt and fuse with the molten alloy when the valve disc 4.- is cast thereon, fusing the valve stem and the valve disc into a solid piece. The valve stem 1- as finished with the threadedend thereon, is placedinto a mold arranged for casting the valve disc, so positioned as to project the threaded section of the valve stem in the center of the valve disc mold, for casting the disc 4 thereon. It

is obvious that the threaded section2 and -3 on the valve stem 1- provides a meansfor engaging and gripping the disc 4-, and resisting any strain therein caused by the action of the operating valve when installed in an engine. The thin sharp thread segments are quickly melted by the contact of the molten alloy when casting the disc "frthereon, and readily fuse therewith, and the alternate interlocking right hand and left hand thread segments arranged on opposite side of the valvestem act to resist any turning of the stem within the valve disc even though a perfect fusion did not take place when the disc was cast thereon.

The thread segments on the valve stem -'1 are formed by a special machine for cutting and forming the right hand thread segments 2 on one side of the stem rod 1-, separately and independently from the left hand thread segments 3- on the opposite side of the stem rod, each alternate right and left hand segment being so positioned as to form an interweaving and interlocking of the segment ends, producing a continuing alternation of,r'ight hand and left hand thread segments. Each thread segment preventing any turning of the valve stem along the opposite thread segi'i'ien t, and which provides a rigid connection between the valve stem 1 and valve .disc t even though no fusion between the metals had taken place.

AnapproXimate semi-segment thread mayalso be formed on the .valve stem rod 1-, by cutting thereon a right hand thread, and -re-cutting a left hand thread .over the same portion of the .rod, but so positioned that the latter thread segments will be opposite the thread grooves on the other side ofthe rod --1-, thus forming short, alternating right hand and left hand "thread segments along the valve stem, similar to the ones formed by the special thread machine.

Having fully described our valve stem and valve, .what weclaim as our invention and desire to secure by Letters Patent is 1. A valve stem comprising a machined cylindrical steel rod having a compound threaded section on one end thereof, said threaded section so formed as to have one side of the rod cut with right hand V-shaped thread segments, and the'opposite side of the rod cut with 'left hand V-shapedthread seg ments, so positioned that alternate right hand and left hand thread segments overlap and interweave at the ends thereof, for retaining avalve disc cast thereon.

2. A valve stem comprising a cylindrical steel rod having a compound threaded section formed on one end :of therochgsaid compound threaded section formed by cutting a right hand thread and a left hand thread over the same section of the valve stem rod, thus forming alternate right hand and left hand thread segments on opposite sides of the rod, said alternate thread segments interweaving and interlapping at the ends thereof, for retaining a valve disc cast thereon.

A valve comprising a cylindrical rod stem having alternate right hand and left hand V-s'haped thread segments formed on opposite sides of the valve stem rod, said alternate thread segments overlapping and interweaving at the ends thereof, and an alloy valve disc cast on the threaded section of the valve stem.

at. A valve comprising a machinedv cyl-indrical steel rod having a compound threaded section formed on one end thereof, said 7 threaded section of the valve rod formed 'by having right hand 'V-shaped thread segments out on one side of the rod and left hand V- shaped thread segments cut on the opposite side of the rod, the ends of each alternate right hand and left hand thread segment interlocking and overlapping each other, and

an alloy valve disc cast on the threaded section of the valve stem.

5. A valve comprising a cylindrical steel rod' having a double threaded section formed at one end thereof, said double threads formed by cutting :a right "hand thread and a left hand thread over the'same section of the rod, forming thereon alternate right hand and left hand thread segments on 013- posite sides of the rod, so positioned Yes to overlap and inter-view the ends .of the thread segments, and analloy valve disc cast .on the threaded portion of the said valve stem.

In witness whereof we sign these specifications.

RAY L. SPITZLEY.

ALLEN M. THOMPSON. 

